As an wner builder you can save some depending how much you do yourself. More importantly you can generally get auch better job if you habe some idea of the trades and who to use etc.

We've done the owner builder thing before, but it was a totally different type of project. What we're looking at is taking a standard 3br redbrick and adding an extra bedroom, a study and a second living room. Just trying to get a really general idea of costs at this stage - ie are we looking at 100k? Assuming it's a flat block with nothing unusual.